Dialog systems are systems that allow a user to interact with a computer system to perform tasks such as retrieving information, conducting transactions, and other such problem solving tasks. A dialog system can use several modalities for interaction. Examples of modalities include speech, gesture, touch, and handwriting. User-computer interactions in dialog systems are enhanced by employing multiple modalities in a coordinated manner. Dialog systems using multiple modalities for user-computer interaction are referred to as multi-modal dialog systems. The user interacts with a multi-modal dialog system by using multiple modalities that are coordinated as a dialog-based user interface. The user interface is referred to as a multi-modal dialog interface. A set of interactions of the user with the dialog system is referred to as a dialog. Each interaction is known as a turn of the dialog. The information provided by either the user or the dialog system is referred to as a context of the dialog.
To effectively use a multi-modal user interface, a user should know which modalities to use and the method of using them, in a coordinated manner in different turns of a dialog. Further, the utilization of the multi-modal user interface of a dialog system can be difficult to use, due either to the lack of experience with using the system, or to changes in the availability and capability of modalities during a dialog.
Known dialog-based systems do not help a user to use different modalities in a coordinated manner. Further, these dialog systems do not take into account modality availability information. Moreover, the dialog systems do not provide a response to the questions asked by users in a dialog related to the use of different modalities.
Those skilled in the art will appreciate that the elements in the figures are illustrated for simplicity and clarity, and have not been necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated, relative to other elements, for an improved perception of the embodiments of the present invention.